Cooling Design of Shielding at MOMENT Cooling Design of Shielding at - - PowerPoint PPT Presentation

Cooling Design of Shielding at MOMENT Cooling Design of Shielding at MOMENT

Jianfei Tong, Qingnian Xu,YuanYe,Binzhou, Tianjiao Liang August 11, 2015 Insititue of High Energy Physics, CAS

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Outline

• 1. Introduction
• 2. Heat Deposition Calculation
• 3. Cooling Structure Design & CFD Analysis
• 4. Conclusion

Page 散裂中子源进展汇报 August 11, 2015

Material: Tungsten Length=8.33 m Diameter=2 m Density=19 g/cc Volume=22.5 m3 Mass=428 t

• 1. Introduction

Proton Shielding Target (Mercury Jet) Shielding

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Function of Shielding:

• 1. Protect equipments from

high radiation 2.Absorb most of heat load from beam power 3.Minimize the heat load on magnets

Target Magnet

Proton beam power =15 MW

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Stainless Steel 304 Aluminum Alloys 6061 Nb3Sn NbTi Tungsten

Stainless steel 304: Fe 0.6775, Si 0.01, Mn 0.02, Cr 0.19, Ni 0.0925, N 0.01. Aluminum Alloys 6061:Al 0.9725, Si 0.006, cu 0.002, Mg 0.01, Zn 0.0025, Mn 0.0015, Ti 0.0015, Cr 0.002, Fe 0.0035. Nb3Sn: Nb 0.482, Cu 0.518. NbTi conductor: polyimide 0.079(polyimide C6H11ON,Density1.41g/cc ), Al 0.731, Cu 0.09, NbTi 0.1 Mecury: Density 13.534 g/cc Tungsten: Density 19.3 g/cc

2.1 Heat deposition: Calculation Model of Fluka

Nb3Sn Mercury

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Proton: 1.5 GeV, 10 mA Target：Hg Length=300 mm, R=5 mm Shielding: Tungsten

Heat deposition for Proton beam power = 15 MW

2.2 Heat deposition: Results

Heat load on Shielding: 9.9 MW Max volumetric heat source=2.2x108[W m^-3]

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3.1 Cooling Structure Design Criterion

• 1. For the shielding material density should be as high as possible,

which reduce the heat load on superconducting magnets, the total volume of cooling channel can reduce the density of shielding and should be as small as possible;

• 2. It’s not a good choice of cooling channel face to magnet, or along

the radius direction, for the particle jet effect; The coolant passing through the shielding from front to rear also can prevent the irradiation damage on magnets;

• 3. Multiple rows of Mini-Channel with reasonable size can increase the

heat transfer area and prevent decreasing the density too much. For the possessing difficulty of the tungsten, the channel should be as simple as possible;

• 4. For the high volumetric heat in shielding, the cooling channel

should be designed to keep the shielding in demand especially near the target.

Front Rear

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• 1. Water : good choice, inexpensive, high thermal conductivity, high material

density, tungsten has to be cladded by tantalum

• 2. Helium : alternative choice, expensive, no new nuclide, tungsten no need

cladded by tantanlum

• 3. Liquid metal (difficulty to deal with new generation of nuclides)

3.2 Coolant choice

Heat Condutivity (W /m-K) Special Heat Capacity (J/kg-K) Visousity (Pa/s) Density (kg/m3)

Water

0.6069 4181.7 8.899e-4 997

Helium@1atm 300K

0.1415 5240 1.86e-05 0.179

Helium@3Mpa 300K

0.158 5191 2.01e-05

4.78

Water: Max velocity 5 m/s； Goal: max temperature of water below 150 ℃ (keep in liquid phase), max temperature of tungsten below 800℃ Helium : Max velocity 100 m/s；Goal: max temperature below 800℃

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60 Cut view O-A B B B-B Case 1 First Wall thickness=1cm

3.3 Cooling Structure design

Case 2 No.1 Cooling Channels No.2 No.3 No.4 No.5 No.6 No.7 Cooling Channels No.1 No.2 No.3 No.4 No.5 No.6 No.7 A O Cut into 60 aliquots

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Finite Volume Method Software: Ansys CFX

3.4 Government Equation & Calculation Software

heat source

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3.5 Calculation Model in CFX

Inlet Velocity in channel Water: 5 m/s Helium: 50,75,100 m/s Inlet Temperature 300 K Outlet Pressure 0 Pa Fluid & Solid Domain Fluid Domain Inlet Outlet Cooling Channels Size: 1cmX1cm Heat capacity (J/kg K) Density (Kg/m3) Thermal Conductivity (W/m K) Viscosity (Kg/m s) Tungsten 134 19000 120 Water 4181 997 0.6069 8.8×10-6 Properties of Tungsten and Water Case 2 Case 1 Symm Symm Volume of Cooling Channels: 0.00384648 m3 Volume of Solid: 0.371984 m3 Volume ratio of Cooling Channels = 1%

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Heat load of shielding @Beam Power= 165053W*60=9.9MW Max volumetric heat source=2.2x108 W m^-3

3.6 Heat source in CFX

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Pressure Drop= 0.8 MPa Outlet T=311.7 K ∆T=11.7 K Mass flow rate=7X997 kg/m3*5 m/s*0.0001 cm2=3.49kg/s Total mass flow rate @ Shielding=206kg/s=744 m3/h

3.7 Results: case 1, water, 5 m/s

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5.0x10

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1.0x10

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1.5x10

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2.0x10

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2.5x10

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3.0x10

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1 2 3 4 5

Density (kg/m3) P (Pa) Density

300 400 500 600 700 800 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

density (kg/m3) T (K) density

300 400 500 600 700 800 5190 5192 5194 5196 5198 5200

cp (J/kg-K) T (K) cp

300 400 500 600 700 800 2.0x10

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2.5x10

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3.0x10

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3.5x10

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4.0x10

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Viscosity (Pa-s) T (K) Viscosity

300 400 500 600 700 800 0.10 0.15 0.20 0.25 0.30 0.35 0.40

Conductivity (W/m-K) T (K) Conductivity

3.8 Properties of Helium

Density @300 K against Pressure Density @3 Mpa against Temperature Special Heat Capacity @3 Mpa Viscosity @3 Mpa Heat Conducivity @3 Mpa

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3.9 Comparison of Pressure: case 1, Helium, 100 m/s

Working Pressure=1 Mpa Working Pressure=2 Mpa T@outlet=2204.2 K T@outlet-T@inlet=1904.2 K Max T=2184.5 ℃ Working Pressure=0.1 Mpa T@outlet=617.5 K T@outlet-T@inlet=317.5 K Max T=713.7 ℃ Pressure drop=0.04 Mpa Pressure drop=0.48 Mpa T@outlet=450.4 K T@outlet-T@inlet=150.5 K Max T=493.1 ℃ Pressure drop=0.83 Mpa

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T@outlet=519.3 K T@outlet-T@inlet=219.3 K Max T=603 ℃

3.10 Comparison of veolicity: case 1, Helium, 3Mpa

Pressure drop=0.54Mpa Velocity=50 m/s Velocity=75 m/s Velocity=100 m/s T@outlet=479.2 K T@outlet-T@inlet=179.3 K Max T=483 ℃ Pressure drop=1 Mpa Pressure Drop=1.5 Mpa T@outlet=428.4 K T@outlet-T@inlet=128.4 K Max T= 418 ℃

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3.11 Comparion of Case 1 & Case 2：Water, 5 m/s

Case 1 Case 2

• For the high heat conductivity of water,

the maximum temperature values of shielding and water in Case 1 and Case 2 are nearly same, but the temperature distribution is slightly different.

• The first wall thickness (position of

No.1 channel ) determines the maximum temperature, in this study, we use 1 cm.

A A A A A A Fluid-solid Couping Surface Fluid-solid Couping Surface

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3.12 Comparion of Case 1 & Case 2：Helium, 100 m/s, 3 Mpa

Case 2 Case 1

Mass flow rate= 0.29879 [kg s^-1] Total flow rate @Shielding=17.92 kg/s The maximum temperature of shielding in Case 2 is higher than Case 1 at current

• conditions. The cooling channel

distribution effect can not be ignored due to cold helium.

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Conclusion

From the Fluka calculation, the total heat load of shielding is about 10 MW and the maximum volumetric heat is above 100 W/cc , which is a challenge work for cooling design . Multiple Rows of Mini-Channel(MRMC), the shape of which is like a fold line to remove the highest volumetric heat, with reasonable channel size(1 cmX1 cm) and first wall thickness(1 cm), and the cooling direction of channel from front to rear, are premiliary ideals in the cooling structure design, and can minimize irradiation demage to magnets. For the corrosion in high temperature, tungsten should be cladded with tantalum, and the coolant water should be kept in single phase, the velocity should be very high. With MRMC and low first wall thickness, helium is a good coolant choice with high pressure and high velocity. Different channel distributions with constant first wall thickness has a different effects on the maximum temperature of shielding based due to the coolent thermal properities. It is possible to remove the high heat load and high volumetic heat on shielding at MOMENT using water or high pressure helium with MRMC.

Page 散裂中子源进展汇报 August 11, 2015

Thank you for attentation